JP2002062397A - Method and apparatus for treating used equipment contaminated with radioactive materials - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a method of treating used equipment contaminated with radioactive substances, which can be efficiently and at low cost to a radioactivity level equivalent to that of general waste. I do. A method for decontaminating equipment contaminated with a radioactive material, wherein the used equipment is decomposed and the decomposed parts are separated into decontaminated parts and non-decontaminated parts. A decontamination step of decontaminating the decontaminated parts separated in the decomposition step, and a survey step of measuring the radioactivity of the parts decontaminated in the decontamination step, In the process of decontamination, a method of immersing in a hand acidic solution, a method of irradiating ultrasonic waves while immersing a part to be decontaminated in an acidic solution, and a method of irradiating ultrasonic waves while immersing parts to be decontaminated in water One of a method of bringing a rotating brush into contact with the surface to be decontaminated of the component to be decontaminated, a method of spraying water on the surface to be decontaminated of the component to be decontaminated, and a method of drying the component to be decontaminated. It is performed by a method combining two or more decontamination methods.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating used equipment contaminated with radioactive materials, and more particularly to a method for treating used equipment used in a uranium enrichment facility and contaminated by contact with UF6. The present invention relates to a processing method and a processing apparatus.

[0002]

2. Description of the Related Art Conventionally, uranium enrichment facilities generally use a large number of centrifuges. During operation, the inside of the centrifuge comes into contact with UF6 and becomes contaminated with radioactive materials. The centrifuge will generate as radioactive waste. If all of these are stored and disposed of as radioactive waste, problems such as securing storage facilities will arise, so it is necessary to treat them to the level of radioactivity equivalent to general waste.

[0003] Most of the centrifuge is made of a metal material. The material of the centrifuge is not only an alloy mainly composed of iron having an oxide film as a rotating body material, but also an aluminum alloy, stainless steel, or the like.
There are many types such as carbon steel. Conventionally, in nuclear facilities and the like, as a method of treating such radioactive metal waste, a method of chemically decontaminating radioactive metal waste by immersing the same in a decontamination liquid such as an acid has been used. As a decontamination method and apparatus aiming at a radioactivity level equivalent to that of general waste, for example, JP-B-7-7104 and JP-A-9-257994
JP-A-10-186 discloses a decontamination method of irradiating ultrasonic waves while immersing in an acid such as sulfuric acid as disclosed in
A decontamination method including a step of injecting water, a step of immersing in nitric acid, a step of ultrasonic cleaning in water, and a step of blasting, as disclosed in Japanese Patent Application Publication No. 090,090, are known. .

[0004]

The internal structure of a used centrifuge is complicated. Even if the used centrifuge is immersed in a decontamination liquid such as an acid as in the above-described conventional example, it cannot be used inside the centrifuge. When it is difficult to recover the decontamination solution that has flowed in, and when ultrasonic waves are used in combination, there are parts where ultrasonic waves do not propagate, making it impossible to effectively decontaminate (obtain a high decontamination coefficient) There are many. Also, in the blasting process, it is necessary to spray the abrasive onto the surface to be processed, but if the used centrifuge is in the assembled state, the abrasive cannot be sprayed onto the surface to be processed, and the inside is sufficiently treated. It was impossible to do.

[0005] On the other hand, used centrifuges have many types of materials, and some have special surface treatments or oxide films. Furthermore, the degree of contamination and the type of contamination differ depending on each component and site. . The conventional decontamination method is a decontamination method in which the contaminated metal surface is immersed in a decontamination solution to chemically dissolve it, or to promote it by combining ultrasonic waves. Equipment for treating the waste liquid that is generated therewith is provided. Even if decontamination processing of a used centrifuge is performed for each component using this decontamination method, if the same decontamination method is applied to components having different surface properties as described above, the decontamination effect between components will be reduced. There has been a problem in that there is a variation in the radioactivity and there is a case where a required radioactivity level cannot be achieved.

[0006] Further, some decontamination is performed excessively more than necessary, and the efficiency of decontamination work is deteriorated. In addition, the amount of metal components dissolved in the decontamination solution is increased, and deterioration of the decontamination solution is accelerated. At the same time, there is a disadvantage that the amount of insoluble sludge generated in accordance with the waste liquid treatment of the decontamination liquid increases. Furthermore, if the above-mentioned decontamination method is combined with a decontamination method that is different in principle, such as blasting, not only a dedicated processing device is required, but also the supply, collection, and waste liquid treatment of the decontamination solution In addition to the equipment, additional auxiliary equipment such as supply and recovery of blast material and the like, secondary waste treatment, and the like are required, and there is a disadvantage that equipment costs increase.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to treat used equipment contaminated with radioactive materials efficiently and at low cost to a radioactivity level equivalent to that of general waste. It is an object of the present invention to provide a used apparatus processing method and a processing apparatus which can perform the processing.

[0008]

That is, the present invention relates to a method for decontaminating used equipment contaminated with a radioactive substance, wherein the used equipment is disassembled and the disassembled parts can be decontaminated. And a decontamination step for separating the components that cannot be decontaminated, a decontamination step for decontaminating the decontaminated parts separated in the decomposition step, and a radioactivity amount of the parts decontaminated in the decontamination step. Having a survey step to measure, and decontamination of the decontamination step, a method of immersing the component to be decontaminated in an acidic solution, and a method of irradiating ultrasonic waves while immersing the component to be decontaminated in the acidic solution, A method of irradiating ultrasonic waves while immersing the component to be decontaminated in water, a method of bringing a rotating brush into contact with the surface to be decontaminated of the component to be decontaminated, and spraying water on the surface of the component to be decontaminated. Decontamination of two or more of a method and a method of drying a component to be decontaminated To carry out by the method of combining law is obtained so as to achieve the intended purpose.

In this case, at the time of the decontamination in the decontamination step, devices for performing the decontamination method are arranged in series, and the used equipment is caused to travel along the arranged rows. For each type of condition related to decontamination properties of the decontaminated parts, such as the material of the decontaminated parts and the properties of the decontaminated surface, use only the necessary decontamination equipment and operate the decontamination time, etc. The decontamination is performed by changing the condition to a condition suitable for the type of the condition relating to the decontamination property of the component to be decontaminated. Further, when the used equipment is a centrifuge contaminated with radioactive material, when disassembling the centrifuge in the disassembly step, the centrifuge is run while being loaded or suspended in a direction perpendicular to the axial direction of the centrifuge. Is transported to the position of the corresponding pull-out / disassembly mechanism, and in this state, the content part of the used centrifuge is pulled out and disassembled by the pull-out / disassembly mechanism in the axial direction of the centrifuge. The disassembly and disassembly of the used centrifuge is repeated by disassembling and transporting the parts to be disassembled in such a way that they are transported to the position of the pull-out / disassembly mechanism to which they are applied and disassembled. It is.

[0010] The present invention also relates to a processing apparatus for used equipment contaminated with radioactive materials for cleaning and decontaminating used equipment contaminated with radioactive substances. And a decontamination device for decontaminating decontaminable components of the decomposed components, and a survey device for measuring the amount of radioactivity of the components decontaminated by the decontamination device. A device for decontaminating the component to be decontaminated by immersing it in an acidic solution, a device for irradiating ultrasonic waves while immersing the component to be decontaminated in an acidic solution, and a device for immersing the component to be decontaminated in water A device for decontamination by irradiating ultrasonic waves while decontamination, a device for decontamination by bringing a rotating brush into contact with the surface to be decontaminated, and a decontamination by spraying water on the surface for decontamination A device and a drying device for drying the parts to be decontaminated, It is obtained by forming so as to decontaminate the spent devices in either of two or more devices of the decontamination apparatus.

Further, in the case where the used equipment is a centrifuge contaminated with radioactive material, the disassembly device is configured to run while loading or suspending the used centrifuge and stop at an arbitrary position. A centrifuge transport mechanism, a travel line that directs the traveling direction of the centrifuge transport mechanism in a direction perpendicular to the longitudinal direction of the used centrifuge, and a centrifuge transport mechanism that is disposed at a plurality of locations along the travel line, A pull-out / disassembly mechanism that pulls out and disassemble the content parts, and disassembles the used centrifuge in order to transport it to the position of the pull-out / disassembly mechanism corresponding to the content part to be disassembled and disassemble the relevant parts. -It is formed so that the contents parts are disassembled by repeating the transportation.

[0012] The decontamination apparatus may include means for immersing the component to be decontaminated in an acidic solution, means for irradiating ultrasonic waves while immersing the component to be decontaminated in the acid solution, and Means for irradiating ultrasonic waves while immersing, means for bringing a rotating brush into contact with the surface to be decontaminated of the component to be decontaminated, means for injecting water onto the surface to be decontaminated of the component to be decontaminated, Decontamination tank, which also has a means for drying, a storage tank for storing an acidic solution or water used for decontamination processing, and a decontamination liquid supply for supplying and recovering the acidic solution or water to the decontamination tank・
Whether it is formed from a collection mechanism and a decontaminated parts transport mechanism for transporting to and from the decontamination tank while suspending the parts to be decontaminated or the washing basket storing the parts to be decontaminated. Alternatively, this decontamination apparatus is a tank for immersing a component to be decontaminated in an acidic solution, a tank for irradiating ultrasonic waves while immersing the component for decontamination in an acidic solution, and an ultrasonic tank for immersing the component to be decontaminated in water. A tank that irradiates the surface to be decontaminated with a rotating brush, a tank that sprays water onto the surface to be decontaminated of the component to be decontaminated, and a tank that dries the part to be decontaminated. Decontamination tank, and a decontamination parts transport mechanism for transporting between the decontamination tanks and taking in and out of each decontamination tank while suspending the parts to be decontaminated or the washing basket storing the parts to be decontaminated. While forming, the respective tanks of the decontamination tank are arranged side by side in series,
In addition, the traveling direction of the component-to-be-decontaminated transporting mechanism is formed so as to be aligned with the decontamination tank.

[0013] The decontaminated component transport mechanism includes a gripper for gripping and suspending the component to be decontaminated or a washing basket containing the component to be decontaminated, and coming into contact with the component to be decontaminated of the gripper. It is formed so that there are at least two portions. Further, the surveying device, a survey detector for detecting the amount of radioactivity on the surface of the component to be measured, a setting mechanism for setting the survey detector close to the surface of the component to be measured, and for rotating the component to be measured And a rotation mechanism, and the survey detector is constituted by an inner peripheral surface detector and an outer peripheral surface detector of the component to be measured, and the detection surface of the inner and outer peripheral surface detector is a surface of the component to be measured. It is formed into a curved shape approximating the circumferential curvature of each of the inner peripheral surface and the outer peripheral surface.

That is, in such a method for treating used equipment, the processing step disassembles the used equipment and separates the disassembled parts into decontaminated parts and non-decontaminated parts. A decomposition step, a decontamination step of decontaminating the decontaminated parts separated in the decomposition step, and a survey step of measuring the amount of radioactivity of the parts decontaminated in the decontamination step; The decontamination in the dyeing process is performed by immersing the component to be decontaminated in an acidic solution, by irradiating the component to be decontaminated with ultrasonic waves while immersing the component in an acidic solution, or by immersing the component to be decontaminated in water. A method of irradiating a sound wave, a method of bringing a rotating brush into contact with a surface to be decontaminated of a component to be decontaminated, a method of spraying water on the surface to be decontaminated of the component to be decontaminated, and a method of drying the component to be decontaminated To be performed by a method combining two or more decontamination methods Al, a short time the entire surface of the unit components of the used centrifuge, that is, become possible to efficiently contamination. That is, the used centrifuge is disassembled into parts, the contaminated surface of each part is opened to make it decontaminable, and the disassembled parts are separated and only the decontaminable parts are decontaminated and given to the decontamination step. Efficient decontamination can be carried out with a minimum load, and therefore, waste equipment contaminated with radioactive materials can be efficiently reduced to the level of radioactivity equivalent to that of general waste.
In addition, processing can be performed at low cost.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 shows a processing flow of a centrifuge which is one of the used devices. Used centrifuges are transported to the disassembly process, disassembled into parts as much as possible, and among the disassembled parts, porous parts such as magnets,
Packings and the like that are not expected to have a decontamination effect are separated as non-decontamination parts, dispensed as radioactive waste, and only decontamination parts are dispensed to the decontamination process.

In the decontamination step, these decontaminated parts are received as parts to be decontaminated, and of the following six decontamination methods having different cleaning functions, the minimum necessary for obtaining a decontamination effect for each part is given. Decontaminate using a combination of decontamination methods.

(1) A method of immersing a component to be decontaminated in an acidic solution, which has a function of dissolving a contaminated portion on a metal surface (FIG. 1)
Acid solution).

(2) Irradiation of ultrasonic waves while immersing a part to be decontaminated in an acidic solution, having both an action of accelerating the dissolution of the contaminated portion of the metal surface in the above-mentioned immersion in the acidic solution and an action of peeling off the contaminants. (Acidic solution ultrasonic cleaning in FIG. 1).

(3) Irradiation of ultrasonic waves while immersing the parts to be decontaminated in water, which has the function of separating contaminants without dissolving the metal surface and the function of preventing the separated contaminants from re-adhering. (Water ultrasonic cleaning in FIG. 1).

(4) A method of bringing a rotating brush into contact with the surface to be decontaminated of the component to be decontaminated, which has a function of scraping off contaminants adhering to the metal surface (brush cleaning in FIG. 1).

(5) A method of injecting pressurized water onto the surface to be decontaminated of the component to be decontaminated, which has a function of washing out contaminants on the metal surface by the injection pressure of water (jet washing in FIG. 1).

(6) A method of forcibly drying a component to be decontaminated having a wet surface by the above-described decontamination method, which has a forced drying action such as circulation of hot air (drying in FIG. 1).

In the above-mentioned decontamination method, the acidic solution and water used as the decontamination liquid are repeatedly used up to the serviceable limit in the decontamination step, and after use, transferred to the waste liquid treatment step and mixed. Dispose of waste liquid. In the survey process, the parts that have been decontaminated are measured for their radioactivity using a scintillation detector that measures the surface contamination density of α and β rays at the same time. After confirming that the decontamination has been completed, the processing is terminated.

If the radioactivity level is not decontaminated to the level of general waste, the process is returned to the decontamination step again and decontaminated. According to the present embodiment, a used centrifuge of a component is disassembled into components in a decontaminable state, and a combination of decontamination methods suitable for the component can be selected, so that efficient processing can be performed. Also, the amount of acidic solution used for decontamination and the amount of waste liquid generated can be reduced,
Equipment costs associated with processing can be reduced.

FIG. 2 is a diagram showing an example of a decomposition method and a decomposition apparatus in the decomposition step. First, as a transport mechanism of the used centrifuge 1, a traveling beam 3 arranged in the X direction in the drawing (a direction orthogonal to the longitudinal direction of the used centrifuge 1);
A centrifuge carry-in mechanism 2 that automatically and remotely travels according to the traveling beam 3, a traveling rail 4 arranged in the X direction, and a centrifuge transport lifter 5 that automatically and remotely travels on the traveling rail 4 are installed. Have been.

A carry-in position (a) and a disassembly position (b), (c), (d), and (e) of the used centrifuge 1 are set, and the disassembly position (b) corresponds to the disassembly position (b). The pull-out / disassembly mechanisms 6 and 7 are installed close to each other, and the disassembly position (c)
(D) In (e), pull-out / disassembly mechanisms 8, 9, and 10 are respectively installed near these positions.

In the drawing, reference numeral 11 denotes a disassembly house surrounding the traveling range of each transport mechanism, and a front chamber 12 having a door 13 and a shutter 14 is installed at a carry-in position (a). The inside of the decomposition house is maintained at a negative pressure.

Next, a method of disassembling the used centrifuge 1 using the disassembling apparatus will be described. First, the door 13 of the used centrifuge 1 is opened, and the used centrifuge 1 is put into the carry-in position (A) in the front room 12. Next, the door 13 is closed, the shutter 14 is opened, and the centrifuge 1 is gripped by the centrifuge loading mechanism 2, raised, and moved to the disassembly position (b). Is put down on the centrifuge transport lifter 5.

At the disassembly position (b), both ends of the used centrifuge 1 are extracted by the extraction / disassembly mechanism 6 and the extraction / disassembly mechanism 7. Next, the centrifuge transport lifter 5 is moved to the disassembly position (C) and stopped, and the contents of the used centrifuge 1 are extracted by the extraction / disassembly mechanism 8. Further, the centrifuge transport lifter 5 is moved to the disassembly position (d) and stopped, and the other content parts of the used centrifuge 1 are pulled out by the extraction / disassembly mechanism 9, and finally the centrifuge transport lifter 5 is disassembled. (E)
Until it stops, and the pull-out / disassembly mechanism 10
By pulling out the content parts remaining in the used centrifuge 1, all the content parts are pulled out from the used centrifuge 1, and the used centrifuge 1 is brought into a state of the body part alone.

A plurality of small parts are assembled with bolts or the like in the content parts pulled out by each of the pull-out / disassembly mechanisms 6 to 10. The bolts or the like are removed in each of the pull-out / disassembly mechanisms 6 to 10 to make small parts. Disassemble until. Here, although not shown in the drawings, each of the pull-out / disassembly mechanisms 6 to 10
It has a box shape, and has gloves and a viewing window on the side so that workers can access it from outside.

Each of the pull-out and disassembly mechanisms 6 to 10 is provided with a dedicated automation mechanism and jigs and tools in consideration of differences in the shape, dimensions, assembling method, and the like of the contents to be pulled out and disassembled. I have. In each of the pull-out / disassembly mechanisms 6 to 10,
Using these equipments, pull-out and disassembly are performed by a remote control of an automation mechanism or a manual operation by a worker using gloves in a dedicated method suitable for each content part.

The centrifuge transport lifter 5 is provided with a function of operating the loaded used centrifuge 1 in the Y direction and the Z direction in addition to traveling in the X direction. )
(D) In (e), the position and height of the used centrifugal machine 1 can be adjusted to the optimum position and height for the content part pulling / disassembling work by the pulling / disassembling mechanisms 6 to 10.

In this embodiment, the method of disassembling the used centrifuge 1 in a horizontal position with the longitudinal direction horizontal has been described. However, the used centrifuge 1 may be disassembled in a vertical position with the longitudinal direction vertical. good. In this embodiment, the pull-out / disassembly mechanism is 5
Although an example in which one is provided has been described, it may be further distributed or may be integrated so as to satisfy the required disassembly work capability.

According to the present embodiment, the functions of the pull-out / disassembly mechanism are decentralized and dedicated, so that automation is facilitated and the burden on the disassembly operator can be reduced. In addition, since all decomposition is performed in a decomposition device in a decomposition house that is isolated from the outside air, exposure of workers to radioactive suspended matter generated by decomposition is sufficiently prevented.

Next, an example of the decontamination method will be described with reference to FIG. As a part to be decontaminated, the decontaminated part decomposed in the previous decomposition step, as a material to be decontaminated, by the type of condition related to the decontamination property of the decontaminated part such as the properties of the decontaminated surface, for example, , Class 1 parts, Class 2 parts, and Class 3 parts and accept them in the decontamination process. In this case, for example, Class 1 is a component mainly composed of iron and having an oxide film,
Class 2 is classified as a component whose material is aluminum alloy or stainless steel, and class 3 is classified as a component that has been subjected to a special surface treatment.

As a decontamination tank for decontaminating these parts to be decontaminated, each of the above-described six decontamination methods in the decontamination step is shown in FIG.
The following six types of decontamination tanks are installed: an acidic solution immersion tank, an acidic solution ultrasonic bath, a water ultrasonic bath, a brush washing tank, a jet washing tank, and a drying tank. A configuration is provided in which a component to be contaminated to be transported is provided.

The decontamination method for each classification will be described below. Parts with an oxide film such as Class 1 are first cleaned with an acidic solution ultrasonic bath in an acidic solution ultrasonic bath to dissolve the oxide film and the underlying metal base material, and to some extent remove the oxide film containing contaminants. Let it. Thereafter, water ultrasonic cleaning is performed in a water ultrasonic bath to further remove the oxide film remaining on the surface of the component, thereby exposing the surface of the metal base material. At this point, if necessary, the remaining contaminants that are not peeled off through a brush cleaning tank are scraped off by brushing.

Next, high-pressure water is sprayed on the surface of the metal base material in a jet washing tank to wash away contaminants remaining on the surface of the metal base material, and then immersed in an acidic solution in an acid solution immersion tank. Further, the surface of the metal base material is dissolved, and contaminants that have penetrated near the surface of the metal base material are completely removed. afterwards,
Rinse by spraying high-pressure water onto the surface of the metal base material in the jet washing tank, and finally forcibly dry it with hot air circulation in a drying tank to complete decontamination.

Parts of category 2, that is, parts made of aluminum alloy or stainless steel having no oxide film, are subjected to acidic solution ultrasonic cleaning in an acidic solution ultrasonic bath, and contaminants adhered by ultrasonic irradiation are removed. In addition, the surface of the metal base material in which the contaminants have penetrated is positively dissolved to remove the contaminants.

The parts of category 3, that is, the parts that have been subjected to special surface treatment, are immersed in an acidic solution immersion tank for a long time to immerse the primary acid solution, and the surface-treated portion containing contaminants is dissolved over time. Furthermore, if necessary, the secondary acidic solution is immersed in a different acidic solution from the primary immersion to remove contaminants from the surface of the metal base material.

Thereafter, jet water washing and drying are performed in the same manner as in Class 1. Here, the decontamination time of each decontamination tank is changed and set to a condition suitable for each of the above classifications, and the same type of decontamination is performed by sharing one decontamination tank. Sulfuric acid, nitric acid, phosphoric acid, oxalic acid, and the like are known as acidic solutions used for decontamination. In this embodiment, a sulfuric acid aqueous solution having a sulfuric acid concentration of 5% was used. FIG. 4 shows an example of the result of the decontamination test using the sulfuric acid aqueous solution.

That is, using a test piece of a used centrifuge part, a method of irradiating ultrasonic waves while immersing in a 5% sulfuric acid aqueous solution is performed for 25 minutes, and then irradiating ultrasonic waves while immersing in water for 5 minutes. The method was repeated three times, and finally a decontamination treatment for drying was performed. Before and after decontamination, the ^U238 radioactivity on the test piece surface was measured with an α-ray detector to confirm the decontamination effect. The U ²³⁸ radioactivity of the test piece after decontamination is a radioactivity level that is 1/10 or less (0.04 Bq / cm ² ) of the standard value for taking out contaminated articles from the controlled area according to the Nuclear Regulation Law. The radioactivity level below that of general waste was achieved.

In this embodiment, the acidic solution immersion tank and the acidic solution ultrasonic tank are used as separate decontamination tanks. A method of decontaminating by stopping ultrasonic irradiation when immersing in an acidic solution with a dyeing tank may be used. According to the present embodiment,
A combination of decontamination methods suitable for components can be selected for components with various materials and different surface properties (existence of special surface treatment or oxide film, degree of contamination, contamination type, etc.)
Effective decontamination becomes possible.

Next, an example of a decontamination method and an example of a decontamination apparatus will be described with reference to FIGS. The parts to be decontaminated received from the preceding decomposition step are roughly classified into large cylindrical parts and other small parts. Large cylindrical parts are received as is, while other small parts are collectively received in a washing basket according to the classification of the decontamination method embodiment described above.

First, a method and apparatus for decontaminating a large component to be decontaminated will be described with reference to FIG. As a decontamination tank for decontaminating the large component 15 to be decontaminated, an acidic solution ultrasonic bath 16
Water ultrasonic bath 17, brush cleaning bath 18, acidic solution immersion bath 1
9, six types of decontamination tanks, a jet washing tank 20 and a drying tank 21, are arranged in series.

As a transport mechanism for the large-sized decontaminated parts 15,
A traveling beam 23 arranged in the direction in which the decontamination tanks are arranged and a decontaminated component transport mechanism 22 that automatically travels by remote control according to the traveling beam 23 are installed. Decontaminated parts transport mechanism 22
Hangers 24 that move up and down and large decontaminated parts 15
Is provided with a finger 25 for catching
The finger 25 has three claws 33a, 33b and 33c. The three nails 33a, 33b, and 33c are limited in use according to the contamination status of the large-sized component 15 to be decontaminated.
a for contaminated parts before cleaning, claw 33b for parts during cleaning,
The nail 33c is for a component after cleaning. Acid solution ultrasonic bath 1
6 and the water ultrasonic bath 17 are provided with an ultrasonic vibrator 29, the brush cleaning bath 18 is provided with a rotating brush 30, the jet water cleaning bath 20 is provided with an injection nozzle 31, and all the decontamination baths are provided. Is provided with an upper lid 32.

A method for decontaminating a large-sized component 15 to be decontaminated using the decontamination apparatus shown in FIG. 5 will be described. The large decontaminated part 15 received from the disassembly process is lifted by the decontaminated part transport mechanism 22, travels to the top of the first decontamination tank according to the classification of the above-described decontamination method embodiment, and stops. I do.

Next, the upper lid 32 of the decontamination vessel is opened, the hanger 24 is lowered, and the large-sized decontamination target component 15 is lowered into the decontamination vessel. Is rotated to raise the hanger 24. The upper lid 32 of the decontamination tank is closed, the corresponding decontamination process is performed, and when it is completed, the upper lid 32 of the decontamination tank is opened. Hanger 2 with claw release position 34 of finger 25 facing inward.
4 is lowered until the lower end of the finger 25 is positioned near the center of the cylinder of the large-sized decontaminated component 15. In this state, the finger 25 is rotated until the corresponding one of the claws 33a, b, and c faces inward, the hanger 24 is raised, and the end of the large-sized decontaminated component 15 is hooked and lifted.

Next, as described above, it is transported to the next decontamination tank,
The decontamination is repeated until the decontamination according to the classification of the embodiment of the decontamination method described above is completed. In the present embodiment, the method of decontaminating the large-sized decontaminated component 15 in the horizontal position in which the longitudinal direction is horizontal has been described. However, the decontamination tank is vertically long and the decontamination is performed in the vertical position in which the longitudinal direction is vertical. You may. In this embodiment,
Although an example in which six types of decontamination tanks are arranged has been described, decontamination tanks not used for decontamination may be omitted, or the decontamination tanks may be integrated with a plurality of decontamination means.

According to the present embodiment, the decontamination tank can be shared between parts having different decontamination methods, so that the operation rate of the decontamination tank can be improved and the number of decontamination tanks can be reduced. In addition, since the component to be decontaminated can be shared by the components to be decontaminated having different degrees of contamination, the amount of decontamination work can be increased and the cost of the decontamination device can be suppressed.

Next, a decontamination method and a decontamination apparatus for a small component to be decontaminated will be described with reference to FIG. FIG. 6A shows an example of a system configuration of a cleaning basket transport mechanism that accommodates small components to be decontaminated, in which a hanging device 37 is attached to a moving mechanism 36 attached to a rail 35. A contaminated decontamination tank 39 and a non-contaminated decontamination tank 40 are arranged side by side in the moving direction.

In this figure, two types of decontamination tanks are omitted from the illustration. However, as in the above-described embodiment of the large-sized decontamination part, an acid solution immersion tank, an acid solution ultrasonic bath, a water It is preferable to arrange six types of decontamination tanks side by side, such as an ultrasonic tank, a brush washing tank, a jet washing tank, and a drying tank. The decontamination rail 35 is moved in the X direction, and the hanging tool 37 is moved to the corresponding decontamination tank position. In addition, a driving mechanism may be provided in the moving mechanism 36 to automatically travel. The lifting device 37 is moved up and down in the Z direction by a lifting device (not shown), and the cleaning basket 38 is lifted and conveyed to the lifting device 37, decontaminated in the decontamination tank 39, and post-treated in the non-contaminated decontamination tank 40. I do.

FIG. 6B shows a working state in the decontamination tank. The contaminating hook 43 and the non-contaminating hook 44 extend downward and upward.
Is provided. The hook is rotated with the rotation shaft 45 as a fulcrum, so that the contamination hook 43 and the non-contamination hook 44 are turned upside down.

In the decontamination work, the cleaning basket 3 containing the small decontaminated parts 40 in the decontamination tank 39 in which the decontamination liquid 41 is stored.
8 is dipped to the tip of the lifting hook with the contamination hook 43. For this reason, if the same hook is used for both before and after decontamination, contamination spreads to non-contaminated articles. In order to prevent this, the hook 43 for contamination and the hook 44 for non-contamination are switched and used.

According to the present embodiment, it is possible to share the transporting mechanism of the parts to be decontaminated between cleaning baskets having different degrees of contamination, so that the amount of decontamination work can be increased and the cost of the decontamination apparatus can be reduced. it can.

Next, an example of a decontamination method and an example of a decontamination apparatus different from those described above will be described with reference to FIG. FIG. 7A shows an example of a system configuration of a decontamination apparatus having a plurality of decontamination means.
The ultrasonic vibrator 2 is placed in the decontamination tank 46 containing the washing basket 38.
9, an upper lid 54, a brush driving mechanism 55, a pressurized water jet nozzle 31, a hot air supply port 57, and a hot air exhaust port 58. Further, an acidic solution storage tank 47 for storing an acidic solution and a water storage tank 48 for storing water are provided, and piping of an acidic solution supply line 49, a water supply line 50, an acidic solution recovery line 51, and a water recovery line 52 are provided, respectively. To the decontamination tank 46. Further, a drain line 53 is connected to the decontamination tank 46.

The cleaning basket 38 containing the small components 42 to be decontaminated is set in the decontamination tank 46, and in this state, the pump and valve of the acidic solution supply line 49 and the water supply line 50 are switched, and Is supplied to the decontamination tank 46. When the acidic solution ultrasonic cleaning and the water ultrasonic cleaning are performed, after the cleaning, the valves of the acidic solution recovery line 51, the water recovery line 52, and the drain line 53 are switched, and the decontamination liquid is recovered to the original place. . By repeating the above-described operation, the processes of ultrasonic cleaning with an acidic solution, immersion in an acidic solution, and ultrasonic cleaning with water are performed in one decontamination tank.

Next, a method of brush decontamination and drying in the decontamination tank 46 will be described with reference to FIG. The upper lid 54 on which the brush driving mechanism 55 is installed is slid horizontally to close. In this state, the brush 56 moves up and down,
The surface of the small component to be decontaminated 42 is decontaminated by a combination of horizontal movement and brush rotation. When drying, cover 54
Is closed, the brush 56 is retracted upward, hot air is supplied from the hot air supply port 57, hot air is exhausted from the hot air exhaust port 58, and the hot air is circulated in the decontamination tank to reduce the size of the component to be decontaminated. Dry 42.

Next, a method of jet water washing in the decontamination tank 46 will be described with reference to FIG. Pressurized water jet nozzles 31 are installed on the left and right sides of the washing basket, and pressurized water 28 is fed under pressure from the pressurized water jet nozzle 31 to small decontaminated parts 4.
2 is sprayed with pressurized water 28. The injected water is
Drain from the drain line 53. Pressurized water injection nozzle 31
Is made of a corrosion-resistant material that withstands the acidic solution because it comes into contact with the acidic solution at the time of ultrasonic cleaning with the acidic solution and immersion in the acidic solution.

According to the present embodiment, a series of decontamination treatments can be performed in one decontamination tank, so that the number of times and time required for transporting the parts to be decontaminated can be reduced, and the decontamination tank and the transport mechanism for the parts to be decontaminated. Installation space can be suppressed.

Next, an example of a survey apparatus will be described with reference to FIG. A rotation mechanism 57 that supports and rotates the cylindrical component to be measured 56; an inner arm 59 in which a plurality of inner detectors 58 are installed; an outer arm 61 in which a plurality of outer detectors 60 are installed; Is configured by a setting mechanism 62 that moves up and down. The detector 58 for the inner surface and the detector 60 for the outer surface are scintillation detectors for simultaneously measuring the α, β ray surface contamination density. Inner surface detector 58
The detection surface 64 and the detection surface 65 of the outer surface detector 60 have a curved surface shape approximate to the circumferential curvature of the inner peripheral surface and the outer peripheral surface of the cylindrical component to be measured 56, respectively.

The cylindrical part to be measured 56 after the decontamination has been completed.
Is placed on the support roller 63 of the rotation mechanism 57. In this state, the rotation mechanism 57 is moved to the arm side, and the arm is inserted. Here, each arm may be moved toward the rotation mechanism 57 to insert the arm. Next, setting mechanism 6
2, the inner surface arm 59 and the outer surface arm 61 are moved in the direction sandwiching the measured component 56, and the detection surface 64 of the inner surface detector 58 and the detection surface 65 of the outer surface detector 60 are brought close to the measured component 56. Let it. In this state, the component to be measured 56 is rotated once by the rotation mechanism 57 and the support roller 63, and the inner and outer peripheral surfaces of the component to be measured 56 for the total length of each detector (the length of the detector × the number of detectors). Measure the surface contamination density.

Next, the measured component 56 is moved in the longitudinal direction by the length of each detector, and the surface contamination density is measured in the same manner as described above.
By repeating this, the surface contamination density of all the inner and outer peripheral surfaces of the measured component 56 is measured. In the present embodiment, the measured component 56 is rotated separately from the longitudinal direction, but may be rotated simultaneously. In the present embodiment, one target component 56 is targeted. However, by adjusting the relationship between the distance between the detection surface of each detector and the target surface and the rotation speed to a relationship that can be measured, a plurality of components can be measured. Measurement can be performed on the measured component 56 having different curvatures.

According to the present embodiment, simultaneous measurement by a plurality of detectors is possible, and it can be shared between parts to be measured having different curvatures.
Equipment costs can be reduced.

As described above, according to the processing method of the used centrifuge, the used centrifuge is disassembled into parts and only the parts that can be decontaminated by separating the disassembled parts are decontaminated parts. And minimizing the load on the decontamination process, and performing effective decontamination on components to be decontaminated with various materials and different surface properties, etc. by combining decontamination methods suitable for the components. Furthermore, since the decontamination effect is confirmed by measuring the amount of radioactivity on the decontaminated parts, the used centrifuge can be processed reliably, efficiently and at low cost to the level of radioactivity equivalent to that of general waste. You can do it.

[0066]

As described above, according to the present invention, used equipment contaminated with a radioactive substance can be treated efficiently and at low cost to a radioactivity level equivalent to that of general waste.

[Brief description of the drawings]

FIG. 1 is a diagram showing a processing flow for explaining a method for processing used equipment contaminated with a radioactive substance of the present invention.

FIG. 2 is a plan view and a side view schematically showing a disassembling method and a disassembling apparatus according to one embodiment of the present invention.

FIG. 3 is a diagram showing a decontamination flow according to one embodiment of the present invention.

FIG. 4 is a diagram showing the results of a decontamination test using a sulfuric acid aqueous solution according to one embodiment of the present invention.

FIG. 5 is a plan view, a side view, and a detailed view of a finger portion schematically showing a decontamination method and a decontamination apparatus according to one embodiment of the present invention.

FIG. 6 is a system configuration diagram schematically showing a decontamination method and a decontamination apparatus according to one embodiment of the present invention, and a detailed view of a decontamination tank section.

FIGS. 7A and 7B schematically show an integrated decontamination tank according to an embodiment of the present invention, wherein FIG. 7A is a system configuration diagram, FIG. 7B is a state diagram at the time of brush cleaning and drying, and FIG. Is a state diagram at the time of jet water washing viewed from above the decontamination tank.

FIG. 8 is a system configuration diagram schematically showing a survey apparatus according to an embodiment of the present invention and a detailed diagram of a detection unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Used centrifuge, 2 ... Centrifuge loading mechanism, 3 ... Centrifuge loading mechanism travel beam, 4 ... Centrifuge loading lifter travel rail,
5: centrifuge lifter, 6: disassembly / pull-out mechanism, 7: disassembly / pull-out mechanism, 8: disassembly / pull-out mechanism, 9: disassembly / pull-out mechanism, 10: disassembly / pull-out mechanism, 11: disassembly house, 12 ...
Front chamber, 13 Front door, 14 Front shutter, 15 Large decontaminated parts, 16 Ultrasonic bath for acid solution, 17 Ultrasonic bath for water, 18 Brush cleaning bath, 19 Acid bath Immersion tank, 2
0 ... Jet washing tank, 21 ... Drying tank, 22 ... Decontaminated component transport mechanism, 23 ... Decontaminated component transport mechanism traveling beam, 24
... Decontaminated component transport mechanism hanger, 25 ... Decontaminated component transport mechanism finger, 26 ... Acid solution, 27 ... Water, 28 ... Pressurized water, 29 ... Ultrasonic vibrator, 30 ... Rotating brush, 31 ...
Pressurized water injection nozzle, 32: decontamination tank upper lid, 33: decontaminated component transport mechanism finger nail, 34: decontaminated component transport mechanism finger nail open position, 35: decontaminated component transport mechanism rail, 36: decontaminated Component transport mechanism moving mechanism, 37 ... Decontaminated component transport mechanism hanging tool, 38 ... Washing basket, 39 ... Contamination decontamination tank, 40 ... Non-contamination decontamination tank, 41 ... Decontamination liquid, 42 ... Small decontamination Parts, 43: Contamination hook, 44: Non-contamination hook, 45: Hook rotating shaft, 46: Decontamination tank, 47: Acid solution storage tank, 48: Water storage tank, 49: Acid solution supply line, 5
0 ... water supply line, 51 ... acid solution recovery line, 52 ...
Water recovery line, 53 drainage line, 54 decontamination tank top lid,
55: brush drive mechanism, 56: component to be measured, 57: rotating mechanism, 58: inner surface detector, 59: inner surface arm, 60
... detector for outer surface, 61 ... arm for outer surface, 62 ... setting mechanism, 63 ... support roller, 64 ... inner surface detection surface, 65
... External detection surface.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) G21F 9/28 561 G21F 9/28 561A (72) Inventor Kazumichi Suzuki 3-chome, Kochicho, Hitachi City, Ibaraki Prefecture 1 Nuclear Power Division, Hitachi, Ltd. 1550 Nuclear Fuel Cycle Development Organization Ningyo Toge Environmental Technology Center (72) Inventor Toshihiro Yamanaka 1550 Kamisaihara Village, Tomata County, Okayama Prefecture Nuclear Fuel Cycle Development Organization Ningyo Toge Environmental Technology Center

Claims (11)

[Claims] 1. A method for decontaminating used equipment contaminated with a radioactive substance, wherein the used equipment is disassembled, and the disassembled parts are separated into decontaminated parts and non-decontaminated parts. Decomposition step to separate, and decontamination step to decontaminate the decontaminated parts separated in the decomposition step, and a survey step to measure the radioactivity of the decontaminated parts in the decontamination step, The decontamination in the decontamination step is a method in which the component to be decontaminated is immersed in an acidic solution, a method in which the component to be decontaminated is irradiated with ultrasonic waves while being immersed in the acidic solution, and the component to be decontaminated is immersed in water. A method of irradiating ultrasonic waves, a method of contacting a rotating brush with a surface to be decontaminated of a component to be decontaminated, a method of spraying water on a surface to be decontaminated of the component to be decontaminated, and a method of drying the component to be decontaminated. And a method combining any two or more decontamination techniques. A method for treating used equipment contaminated with radioactive materials, characterized in that: 2. At the time of decontamination in the decontamination step, devices for performing the decontamination method are arranged side by side in series, and the used equipment is caused to travel along the side by side rows. For each type of condition related to decontamination property of the component to be decontaminated, such as the material of the component to be decontaminated and the properties of the surface to be decontaminated, use only necessary decontamination equipment, and set the operating conditions such as decontamination time. 2. The method for treating used equipment contaminated with radioactive substances according to claim 1, wherein the decontamination is performed by changing the condition to a condition suitable for the type of condition relating to the decontamination property of the component to be decontaminated. 3. The method for treating used equipment contaminated with radioactive substances according to claim 1, wherein the used equipment is a centrifuge contaminated with radioactive substances. 4. When disassembling the equipment in the disassembling step, the used centrifuge is run while being loaded or suspended in a direction perpendicular to the axial direction of the centrifuge, and pulling out and disassembly corresponding to the content part to be disassembled is performed. Transported to the position of the mechanism, and in this state, the used components of the used centrifuge are pulled out in the axial direction of the centrifuge by the pull-out / disassembly mechanism to disassemble, and then the pull-out / decomposition corresponding to the next content component to be disassembled is performed. 4. Contaminated with a radioactive substance according to claim 3, wherein the contents of the used centrifuge are disassembled by repeating disassembly / transportation sequentially so that the parts are disassembled and conveyed to the position of the disassembly mechanism. How to treat used equipment. 5. A processing apparatus for a used apparatus contaminated with a radioactive substance for cleaning and decontaminating a used apparatus contaminated with a radioactive substance, comprising: a decomposition apparatus for disassembling the used apparatus; A decontamination device that decontaminates decontaminable components among the decomposed components, and a survey device that measures the radioactivity of the components decontaminated by the decontamination device, and the decontamination device, A device that immerses the parts to be decontaminated in an acidic solution for decontamination, an apparatus that irradiates ultrasonic waves while immersing the parts to be decontaminated in an acidic solution, and an ultrasonic apparatus that immerses the parts to be decontaminated in water A device for decontamination by irradiating the surface of the component to be decontaminated, a device for contacting the surface to be decontaminated with a rotating brush, and a device for decontamination by spraying water on the surface to be decontaminated of the component to be decontaminated, A drying device for drying the component to be decontaminated, and the decontamination device Any two or more of the processing apparatus of the used equipment that has been contaminated with radioactive material, characterized in that it formed so as to decontaminate the spent equipment apparatus of. 6. The apparatus for treating used equipment contaminated with radioactive substances according to claim 5, wherein the used equipment is a centrifuge contaminated with radioactive substances. 7. A centrifuge transport mechanism formed so that the disassembling device travels while loading or suspending a used centrifuge and stops at an arbitrary position, and uses a traveling direction of the centrifuge transport mechanism. A traveling line oriented in a direction perpendicular to the longitudinal direction of the centrifuge, and a pull-out / disassembling mechanism arranged at a plurality of positions along the traveling line to pull out and disassemble the contents of the used centrifuge. 7. The disassembly / disassembly unit is configured to disassemble the contents parts by repeating disassembly / conveyance sequentially so that the used centrifuge is conveyed to the position of the pull-out / disassembly mechanism corresponding to the contents parts to be disassembled and disassembled. Processing equipment for used equipment contaminated with the radioactive material described. 8. The decontamination apparatus comprises: means for immersing a component to be decontaminated in an acidic solution; means for irradiating ultrasonic waves while immersing the component to be decontaminated in an acid solution; Means for irradiating ultrasonic waves while immersing, means for bringing a rotating brush into contact with the surface to be decontaminated of the component to be decontaminated, means for injecting water onto the surface to be decontaminated of the component to be decontaminated, Decontamination tank, which also has a means for drying, a storage tank for storing an acidic solution or water used for decontamination processing, and a decontamination liquid supply for supplying and recovering the acidic solution or water to the decontamination tank A collection mechanism, and a decontamination parts transport mechanism for carrying the decontamination parts or the cleaning basket storing the decontamination parts to the decontamination tank while transferring the decontamination parts to and from the decontamination tank. Item 6. A treatment device for a used device contaminated with a radioactive substance according to item 6 or 7. 9. The decontamination apparatus includes a tank for immersing the component to be decontaminated in an acidic solution, a tank for irradiating ultrasonic waves while immersing the component for decontamination in the acid solution, and immersing the component for decontamination in water. A tank for irradiating ultrasonic waves, a tank for bringing a rotating brush into contact with the surface to be decontaminated of the component to be decontaminated, a tank for spraying water on the surface for decontamination of the component to be decontaminated, and a tank for drying the component to be decontaminated. And a decontamination component transporting the decontaminated component or the cleaning basket containing the decontaminated component while transporting between the decontamination tanks and taking in and out of each decontamination tank. And the tanks of the decontamination tank are arranged side by side in series, and formed so that the traveling direction of the component-to-be-decontaminated transporting mechanism is the direction in which the decontamination tanks are arranged. An apparatus for treating used equipment contaminated with a radioactive substance according to claim 6 or 7. 10. The decontaminated component transport mechanism includes a gripper for gripping and suspending a component to be decontaminated or a washing basket containing the component to be decontaminated, and coming into contact with the decontaminated component of the gripper. The part is at least two places or more.
A treatment device for used equipment contaminated with any of the radioactive substances described in any of the above. 11. The survey device, wherein a survey detector for detecting the amount of radioactivity on the surface of the component to be measured, a setting mechanism for setting the survey detector close to the surface of the component to be measured, and With a rotation mechanism for rotating, the survey detector is configured from an inner peripheral surface detector and an outer peripheral surface detector of the component to be measured,
The detection surface of the inner / outer peripheral surface detector is formed in a curved surface shape approximating the circumferential curvature of each of the inner peripheral surface and the outer peripheral surface of the component to be measured. Processing equipment for used equipment contaminated with radioactive materials.